TPL Path Labs offer services in immunohistochemistry, not only for your preferred tissue biomarker and novel biomarkers of interest for personalized medicine, but also for the in vitro screening and the characterisation of novel large molecules such as therapeutic monoclonal antibodies.

For this purpose, we are now capable of providing the full services required for executing Tissue Cross Reactivity (TCR) studies according to the current guidelines. In near future we will also be capable of providing you with positive and negative control tissues, including cell lines, which are paramount for method development and validation.

Note to pictures above:

the increase of signal due to the increasing concentration, defining the linear range of test item concentration. The optimum concentration, defined as the lowest concentration of the plateau range interval right after linear range was set in this particular validation study at 1mg/L.

To offer customised TCR services with validated study-specific protocols reflecting the regulator´s requirements and your needs in a cost- and time-efficient manner, we use the classical three-phase approach:

This phase is the most critical and of the greatest importance for the rest of the program. At TPL, we pay most attention to the initial protocol development so to ensure the smooth running of the subsequent GLP phase. Methods will be developed on an automated platform if feasible or, if not possible, manually. Method development will be exclusively science- and data-driven.

Our assay development complies with the most recent guidelines on analytical validation of IHC assays, the outcome of which is a qualitative assessment. Our fit-for-purpose validation is rigorous, and enables us to inform you promptly on the outcome of the method validation progress. You will be immediately informed about the most critical validation parameters in order to rapidly aid you with subsequent steps.

Validation parameters:

target staining specificity

tissue preparation (matrix) effects

test item staining sensitivity (i.e. how low in concentration can we go and still detect a specific staining)

concentration-staining response curve (linear range, plateau range)

optimum concentration for staining (the lowest concentration of the plateau range)

intra-run repeatability

inter-run repeatability (reproducibility).

The validation results may be assessed qualitatively, semi-quantitatively with a grading or using the H-scoring or may be quantitative using an image analysis system (Slide Scorer HS analysis).

In order to refine staining conditions in various tissues (matrix effects), notably to have a preliminary evaluation of background staining within different tissue types, as well as a first evaluation of possible on-target or off-target staining, a non-GLP screening phase may be conducted. This can be useful for the preparation of the definitive GLP study as well.

The common format of this approach is twelve tissues of two different donors. A TMA (Tissue Micro Array) format screening all tissues requested by FDA and EMA is also possible and encouraged, especially for first in class biopharmaceuticals. Here, a screen of model animal species after validating cross species reactivity may be performed, prior to conducting in vivo safety (toxicology) studies.

In Phase 3 the main GLP-compliant TCR study is performed on a panel of 38 human tissues/organs from a minimum of three unrelated, non-diseased donors as required by FDA and EMA.

Turn-around time for these studies including the reporting phase (draft 1) is 2 months if automatic method is applicable, or 3 months if a manual method is to be used. Data is entered in Excel files, printed, dated and signed. Our QA will assure data integrity and our reports include images of significant staining.